Process for manufacturing a contacting device, contacting device and its use

ABSTRACT

An end (2) of an electrical connecting line (1) for feeding a switching current is connected in an electrically conductive fashion, engaging through a recess (4) of a contact support (3), to a contacting piece (7) arranged on the contact support (3). 
     In order to simplify the manufacture of such a contacting device, it is provided that the one end (2) is connected to an extension (10) which is formed by a stamping process in which the recess (4) of the contact support (3) is used as a shaping tool for the extension (10). It is thus ensured that the dimensions of the extension (10) are matched in an optimum fashion to the dimensions of the recess (4). In addition, due to the production of the extension (10) in the recess (4) itself, the positioning of the end (2) bearing the extension (10) relative to the contact support (3) or to its recess (4) is dispensed with. 
     The contacting device can be manufactured, in particular for switchgear and relays.

BACKGROUND OF THE INVENTION

The invention relates to a process for manufacturing a contacting devicein which an end section of an electrical connecting line is guided to afirst flat side of a leaf-shaped contact support, led through a recessof the contact support and connected in an electrically conductivefashion to a contacting piece on the second flat side of the contactsupport lying opposite. In addition, the invention relates to acorrespondingly designed contacting device and a use of this contactingdevice.

From the German Registered Utility Model 81 09 089 a contacting deviceis already known which is manufactured in the way mentioned at thebeginning. In this publication, for the purpose of feeding a switchingcurrent from one side of the contact support engaging through a recessof the contact support constructed as a punch-through, one end of anelectrical connecting line is connected in an electrically conductivefashion to a contacting piece on the other side of the contact support.The one end of the electrical connecting line and the recess of thecontact support, respectively, have to be exactly matched to one anotherin their dimensions in order to permit the one end to be fed through therecess in a fashion which is as free of play as possible and yet assimple as possible. In particular when manufacturing relatively smallcontacting devices, the positioning of the one end relative to therecess of the contact support is difficult and causes an additionalproduction expenditure which contributes to the production costs. In thecase of changes to the dimensions of the recess of the contact support,whether they be constructionally necessary changes or due to tool wear,matching of the tool which manufactures the one end is required.

European reference 0,167,688 (corresponding to U.S. Pat. No. 4,647,743)already discloses a contacting arrangement in which a connecting line inthe form of a stranded conductor is connected directly to a contactingpiece. This publication is particularly concerned with the problem thatthe contact support in the form of a central contact spring is to beprovided on both sides with a contacting piece. In order to cold weldthe connecting stranded conductor it is therefore proposed in thispublication to allow one of the contacting pieces to extend over thewidth of the contact spring end and to cold weld the stranded conductorto the protruding part. The second contacting piece is constructed inthis publication as a contacting rivet with a round cross-section whichis connected by a corresponding projection, engaging through a hole ofthe spring, to the elongate contacting piece first mentioned. Theseround contacting pieces require a relatively high degree of productionexpenditure; in addition, there is the risk that the two associatedcontacting pieces are rotated in the hole of the contact spring bytensional forces on the stranded conductor, as a result of which theposition of the elongate contacting piece in relation to itscorresponding contacting element would change.

SUMMARY OF THE INVENTION

The object of the invention is to provide a process of the typementioned at the beginning and a corresponding contacting device whichis as easy and economical to manufacture as possible, in which case inparticular a direct connection of a connecting line both in a singlecontact to the contacting piece of the contact support and in a switchcontact to both contacting pieces of a central contact spring ispossible, and contacting pieces which are as economical as possible canbe used.

According to the invention, the object relating to the process isachieved in that the end section of the connecting line is placed with apressed-flat longitudinal side parallel on the first flat side of thecontact support, covering the recess on all sides, in that an extensionis stamped out of the end section of the connecting line perpendicularlyto the flat side through the recess of the contact support and in thatduring the stamping process the contact support itself serves as ashaping tool with the contour of the recess.

Since the recess of the contact support is used as a shaping tool forthe stamping process for manufacturing the extension, the extensionformed in this way is always matched exactly to the dimensions of therecess of the contact support, even if these dimensions should varyduring a production batch. In addition, changes to the geometry of therecess are possible over wide areas without costs arising for a changeof a tool producing the extension. A further advantage of the processaccording to the invention consists in the fact that after the stampingprocess the extension already engages through the recess of the contactsupport in a fashion which is free of play and non-positively engagingand thus additional production steps for the positioning of theextension relative to the recess and for feeding through and fixing theextension are dispensed with. It is also advantageous that no exactlyprestamped contacting rivets with a cross-section matched to the recessof the contact support have to be used. Cost-effective cold weldedcontacts can thus be used which are simply cut off the tape and coldwelded on.

In the process according to the invention, the internal circumferentialwalls of the recess in the contact support extend perpendicular to theirflat sides so that the extension also assumes the shape of a column withcircumferential walls extending perpendicular to the flat sides. Anundercut or conical design of the bore in the contact support, as in theknown extrusion riveting of contacting pieces, is not required here,since the contacting piece is of course connected to the extension fromthe opposite side. With respect to the transport of the semi-finishedproduct during the following production steps, in particular up to theconnection of the contacting piece to the extension, it may beadvantageous to connect the extension to the contact support after thestamping process. This can occur by means of a simple soldering; howeverother Joining methods, for example bonding, are also conceivable. Inaddition, in a post-stamping process a further shaping of the extensioncan be performed such that the extension extends in a rivet head-likefashion outside the recess in order to form a positively-engagingconnection. The recess preferably has a noncircular cross-section; bymeans of a cross-section of, for example, corner-shaped construction arotational movement of the extension in the recess is reliablyprevented. Thus, the extension is prevented from moving relative to therecess or from slipping out of the recess of the contact support.

Furthermore, it is expedient that the end section of a connecting lineconstructed as a stranded conductor is compressed in a plate shapebefore being applied to the contact support, in which case, for example,the individual conductors of the stranded conductor are cold welded. Inthis way, a particularly exact geometry of the extension can be achievedbecause the compressed material of the connecting line can be stampedbetter. This is particularly advantageous if the extension is toprotrude on the second flat side lying opposite.

It is particularly cost-effective if a plurality of contacting devicesare manufactured in series production and initially a continuous lengthof connecting lines with alternately non-compressed and compressedconductor sections is manufactured, in each case a compressed section isthen applied as end section of a first connecting line to a contactsupport and stamped into the recess and finally a protruding portion iscut off the stamped section which forms an initial section of a furtherconnecting line. This considerably simplifies the handling of largenumbers because during the stamping process the connecting lines of aplurality of successive contacting devices are still Joined and thus donot have to be transported as individual pieces.

In addition, according to the invention a contacting device with acontact support in the form of a leaf spring which has a recess, aconnecting line arranged on a first flat side of the support and acontacting piece which is arranged on the second flat side of thesupport and connected in an electrically conductive fashion to a sectionof the connecting line led through the recess, is provided in which theconnecting line lies with a plate-shaped end section on the first flatside of the support, in which an extension is stamped out of theplate-shaped end section perpendicularly to the flat side of thesupport, extends through the recess at least over the entire thicknessof the support and is connected to the contacting piece on the secondflat side of the support. Preferably, the recess of the contact supporthas a non-round cross-section as does the extension of the connectingline. In this way, twisting of the extension and of the contactingpieces connected to the connecting line is reliably avoided, which isimportant particularly in the case of elongate solder contacts.

If, in addition, the surface of the end section of the connecting linefacing away from the contact support is provided with a secondcontacting piece, it is expedient that this plate-shaped end sectiondecreases in thickness in a wedge shape towards the free end of thesupport. Thus, the angular movement of the contact support, that is tosay, for example, of a contact spring connected to an armature, can beallowed for. If in fact the respective corresponding contact elementsare located parallel to one another, this wedge-shaped arrangement ofthe contacting pieces on the end section of the connecting line canensure that the respective contacting piece in the respective switchingposition is also located parallel to the corresponding contact element.

BRIEF DESCRIPTION OF THE DRAWINGS.

The features of the present invention which are believed to be novel,are set forth with particularity in the appended claims. The invention,together with further objects and advantages, may best be understood byreference to the following description taken in conjunction with theaccompanying drawings, in the several Figures in which like referencenumerals identify like elements, and in which:

FIG. 1 shows components of a contacting device, manufactured inaccordance with the process according to the invention, in theunassembled state;

FIG. 2 shows a contacting device manufactured in accordance with theprocess according to the invention, in section;

FIG. 3 shows a tool used for carrying out the process according to theinvention;

FIG. 4 shows a diagrammatic illustration of the execution of the processaccording to the invention in the form of series production and

FIG. 5 shows a contact support as a central contact spring inlongitudinal section with contacting pieces arranged in a wedge shape.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows an electrical connecting line 1 in the form of a copperstranded conductor as a component of a contacting device, the saidconductor having an end section 2 compressed by means of a cold weldingprocess. A contact support 3 of the contacting device is provided with arecess 4. The recess 4 has a circular cross-section which is reduced byone segment. In the course of a joining process by means of a stampingtool not shown in FIG. 1, the end section 2 of the electrical connectingline 1 is guided towards the one flange side 3a of the contact support 3in the direction of the arrows 5; in the same way, a contacting piece 7is guided towards the opposite flat side 3b of the contact support 3, asshown by arrows 6. In addition, a second contacting piece 17 can beplaced on the flat side 2b of the end section, as shown by the arrows15.

FIG. 2 shows the components of the contacting device according to FIG. 1in the assembled state after the stamping process. The one end 2 of theelectrical connecting line 1 has an extension 10 which is stamped out ofthe flat side 2a perpendicularly to the surface, which engages throughthe recess 4 of the contact support 3 and is cold welded on its end face11 to the contacting piece 7 forming an electrical connection 12. Duringthe stamping process, the circular cross-section 4a of the recess 4which is reduced by one segment 4b causes the extension 10 to beconstructed in the forth of a cylinder with a corresponding flatteningof its outer surface. As a result, a twisting of the extension 10 in therecess 4 is prevented. In order to improve the electrical conductivityof the connection 12 the contacting piece 7 is plated with a silverlayer 13. The contacting device produced in this way can be, forexample, part of a relay, as described in general in the GermanRegistered Utility Model 83 25 986 with its magnet system. In thispublication, the armature of the relay would be connected to the contactsupport 3 constructed as a contact spring. It is also conceivable toinsert the illustrated contacting device according to FIG. 2 in achange-over contact arrangement, the contacting piece 17, which isillustrated in FIG. 2 by dot-dash lines, being connected in anelectrically conductive fashion to the flat side 2b of the end section 2of the electrical connecting line 1 facing away from the extension 10.The cold welded face formed by the side 2b is constructed during thestamping process in such a way that it is ensured that the quality ofthe electrical connection to the contacting piece 17 corresponds to thatof the connection 12.

FIG. 3 shows a tool which can be used for manufacturing the contactingdevice and consists of an upper part in the form of a punch 20 and of areceiving element 21 cooperating with this punch. The punch 20 can bemoved in the vertical direction 22 and can be lowered with a pressuresufficient for deforming, for example, an electrical connecting lineconstructed as a copper stranded conductor. The end section 2 of theelectrical connecting line 1 and the contact support 3, at least withits area having the recess 4, are inserted into this tool. By means ofthe pressure generated by the punch 20, the material of the end section2 is shaped by engaging through the recess 4 of the contact support 3with the formation of the extension 10. The receiving element 21 has aslight depression 21a with circular cross-section, the diameter of thesaid depression being roughly matched to the recess 4. If the diameterof the depression 21a is greater in dimension than the recess 4 with anessentially circular cross-section, the material of the end section 2flows in accordance with the depression 21 a after the actual stampingprocess so that a rivet head-like, positively-engaging fixing of theextension 10 in the recess 4 is provided. The extension 10 formed inthis way extends through a plane 23 formed by the lower face of thecontact support 3 in accordance with FIG. 3 and projects above thecontact support 3 on this side. The receiving element 21 can serve atthe same time as a cold welded tool for producing a cold weldedconnection to the contact support 3 by means of electrical resistancecold welding, the said cold welded connection fixing the extension 10 inthe recess 4. In order to complete this arrangement to form a contactingdevice in accordance with FIG. 1 or 2, a contacting piece 7 or 17 isapplied in an electrically conductive fashion on one side or on bothsides to the extension 10 or to the side of the end section 2 of theelectrical connecting line 1 facing away from the extension 10. Withcorresponding construction of the punch 20 or of the receiving element21, this can occur directly after the stamping process.

FIG. 4 shows diagrammatically a process for the successive manufactureof a plurality of contacting devices (series production), one stampingprocess step 30 and one cutting process step 31 being illustrated indetail as process steps. A punch 32 can be moved up and down in thevertical direction 33 and forms with a receiving element 34 a stampingtool in accordance with FIG. 3. The punch 32 has an incline 36 so thatthe electrical connecting line 1 can move away from the contact support3 at a predeterminable angle 35. A length 37 has alternatelynon-compressed sections 38a, 38b and compressed sections 39a, 39b. Ifrequired, after further work stations the cutting process step 31follows in the course of the series production, with which step thecompressed section 39a of the length 37 is cut by means of a cuttingdevice 40. A first portion 41 of the compressed section 39a is formedwhich forms the end section 42, provided with the extension, of anelectrical connecting line 43 which is produced complete when thesection 39b of the length 37, which is compressed directly afterwards,is cut in the same fashion. A second portion 44, formed by cutting, ofthe compressed section 39a forms an initial section 45 of a furtherelectrical connecting line 46 of a preceding contacting device (notillustrated in more detail), the said initial section 45 serving for theexternal connection of this electrical connecting line 46.

In FIG. 5, a modified embodiment of the contacting device is shown. Thecontact support 3 is illustrated in a lateral sectional view in the formof a contact spring connected to an armature 8. The compressed endsection 9 of the connecting stranded conductor 1 is shaped in this caseso as to run towards the free end in a wedge shape, which is indicatedby the angle α drawn in exaggerated form. Accordingly, the contactingpieces 7 and 17 cold welded onto the extension 10 or onto the rear 9b ofthis end section also form a gentle angle with respect to one another.This angle is matched to the angular movement of the armature 8 and,with the customary dimensions and contact spaces, is approximately ofthe order of magnitude of up to 5°. By means of this wedge-shaped designit is possible for the respective contacting piece to be located inevery switching position in each case approximately parallel to theassociated corresponding contact element. In the present example, thecontact piece 7 is thus essentially parallel to the correspondingcontact element 18. If the armature is swiveled into the secondswitching position, the contact spring assumes the position 3' whilstthe contacting piece 17 or 17' is now located parallel to thecorresponding contact element 19.

By means of the described process, a contacting device can be providedin a simple fashion, in which device an extension of one end of anelectrical connecting line is matched in an optimum fashion to a recessof a contact support, in that the recess itself serves as a tool formanufacturing the extension. Already during production, the extension iscorrectly inserted and positioned in the recess and with a constructionof the stamping tool (receiving element) as described above is connectedto the contact support in a positively-engaging fashion and thus forms aconstructional unit which is easy to handle during the furtherproduction process.

The invention is not limited to the particular details of the method andapparatus depicted and other modifications and applications arecontemplated. Certain other changes may be made in the above describedmethod and apparatus without departing from the true spirit and scope ofthe invention herein involved. It is intended, therefore, that thesubject matter in the above depiction shall be interpreted asillustrative and not in a limiting sense.

What is claimed is:
 1. A process for manufacturing a contacting devicecomprising the steps of: guiding an end section of an electricalconnecting line to a first flat side of a leaf-shaped contact support,forcing the end section through a recess of the contact support andconnecting the end section in an electrically conductive fashion to acontacting piece on a second flat side lying opposite the first flatside, the end section of the connecting line being placed parallel witha pressed-flat longitudinal side on the first flat side of the contactsupport, covering the recess on all sides, an extension being stampedout of the end section of the connecting line perpendicularly to thefirst flat side through the recess of the contact support, and duringthe stamping process the contact support serving as a shaping tool witha contour of the recess.
 2. The process as claimed in claim 1, whereinthe extension is connected to the contact support after the stampingprocess.
 3. The process as claimed in claim 1, wherein the end sectionof a connecting line i.e. a stranded conductor and is compressed in aplate shape before being applied to the contact support.
 4. The processas claimed in claim 1, wherein the recess in the contact support ispreformed with circumferential walls extending essentiallyperpendicularly to the first and second flat sides.
 5. The process asclaimed in claim 4, wherein during a series production of contactingdevices, a continuous length of connecting lines with alternatelynon-compressed and compressed sections is initially manufactured,wherein a compressed section is then placed as end section of a firstconnecting line on a contact support and stamped into the recess, andwherein a protruding portion is then cut off the compressed sectionwhich portion forms an initial section of a further connecting line. 6.The process as claimed in claim 4, wherein a free surface of the endsection facing away from the contact support is connected directly to asecond contacting piece.
 7. The process as claimed in claim 3 during aseries production of contacting devices, a continuous length ofconnecting lines with alternately non-compressed and compressed sectionsis initially manufactured, wherein a compressed section is then placedas end section of a first connecting line on a contact support andstamped into the recess, and wherein a protruding portion is then cutoff the compressed section which portion forms an initial section of afurther connecting line.
 8. The process as claimed in claim 3, wherein afree surface of the end section facing away from the contact support isconnected directly to a second contacting piece.
 9. A contacting devicecomprising a contact support in the form of a leaf spring which hasrecess, a connecting line arranged on a first flat side of the supportand a contacting piece arranged on a second flat side of the support,the contacting piece being electrically connected to a section of theconnecting line forced through the recess, the connecting line lyingwith a plate-shaped end section on the first flat side of the support,an extension being stamped out of the plate-shaped end sectionperpendicularly to the first flat side of the support and extendingthrough the recess at least over the entire thickness of the support andconnected to the contacting piece on the second flat side of thesupport.
 10. The contacting device as claimed in claim 9, wherein therecess of the support and the extension of the connecting line have across-section which is non-round to the same degree.
 11. The contactingdevice as claimed in claim 10, wherein the plate-shaped end section ofthe connecting line decreases in thickness in a wedge shape in adirection of a free end of the support.
 12. The contacting device asclaimed in claim 9, wherein the contacting device is arranged in anelectromagnetic relay, the contact support being connected as a centralcontact spring to a change-over contact arrangement with a swivellablearmature in the electromagnetic relay.